The following description is provided to assist the understanding of the reader. None of the information provided or references cited is admitted to be prior art.
After acute myocardial infarction (AMI), the immediate therapeutic goal is to establish patency of the infarct-related artery. The successful restoration of epicardial coronary artery patency, however, does not necessarily translate into improved tissue perfusion. Structural disruption or obstruction of the microvasculature, the so-called “no-reflow” phenomenon, could occur before or because of percutaneous coronary intervention (PCI) and can impair coronary flow. Patients with the no re-flow phenomenon have a poor clinical prognosis. The no re-flow phenomenon is generally associated with the presence of an anatomic zone of no re-flow in the tissue. Advances in imaging modalities have improved visualization of no re-flow, showing its frequency to be higher than was estimated by clinical judgment alone. This phenomenon is important because it correlates with infarct size and provides useful prognostic information. No re-flow is associated with reduced left ventricular ejection fraction, left ventricular remodeling, and poor clinical outcomes, placing patients with this effect in a high-risk group among reperfused patients. Attention has shifted, therefore, away from merely achieving epicardial artery patency and towards the status of the microvasculature which can lead to anatomic zones of no re-flow.